Handling Time Zones

[abrae005]

I'm trying to build an "Event Calendar" app for a global user base. The app is based on a SharePoint list.

Right now, I have 4 fields in my list for Date/Time:

• Event Start Date - Date/Time format, with no Time
• Event Start Time - Text
• Event End Date - Date/Time format, with no Time
• Event End Time - Text

Ideally, I'd like users to be able to enter events in their own time zone, and have it automatically display in the time zone of the user who is viewing it.

I can add additional columns to SP if it would make things easier. Within the app itself, there is filtering to display various icons based on "Is there an event on this date?"

Filter(
        'Event Calendar',
        'Event Start Date' <= DateAdd(_FirstDayInView, ThisItem.Value, Days),
        'Event End Date' >= DateAdd(_FirstDayInView, ThisItem.Value, Days)
    )

So, my questions are:

1. Within the App, I'm creating an input form. What fields should I include, and is there code I need to add when saving to capture the time zone info of the user who is saving?
2. On the Calendar View, how do I retrieve the time zone in the current user's local time, which may be different from the time zone that was originally saved?

[v-yutliu-msft]

Hi @abrae005 ,

Do you want to transfer time based on current user's time zone?

If so, I suggest you try TimeZoneOffset() function, which will return time interval between local time zone and UTZ.

Formula like this could convert current time to utc.

DateAdd( Now(), TimeZoneOffset(), Minutes )

In your issue, I suggest you:
1)create a timezone field(number type)

use data like this to update:

-TimeZoneOffset()/60

This will  capture the time zone info of the user who is saving.

For example: 

My local time is 3:pm, utc is 7am.

Then by using this formula, my time zone is 8, which means that my local time is quicker 8 hours than utc.

2)you could compare current time zone with data in timezone field

For example:

current time zone:

-TimeZoneOffset()/60

 data in timezone field:

ThisItem.timezone

If current time zone is 2, data in timezone field is 8, then local time is slower 6 hours than timezone that this field was created.

You could use DateAdd to transfer between them.

I suggest you know more about these functions:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/functions/function-dateadd-datediff

Best regards,

[abrae005]

Hi @v-yutliu-msft ,

Your advice seems to be working partially. I added a field to my SP List called TZ_Offset_Hours, and am using 

-TimeZoneOffset()/60

to populate that. It is correctly showing my time zone as UTC -4.

However, the form seems to be not converting correctly. I created an item with an End_DT_UTC of 9/3, 02:01 AM. That form field should be in UTC. When I look in SharePoint, it shows up as 9/2, 23:01. But, since my UTC offset is -4, it should be 22:01.

Additionally, I want to, on my form, have users enter the time in their local time, and not need to convert that to UTC. I'm guessing I need to add new input fields for that, and then add logic to have that populate the "default" form fields with the conversion?

Lastly, my "Calendar View" is not filtering correctly. I set the "OnVisible" property of my warning icon to:

/*Visible if calendar events are found on this day*/
!IsEmpty(
    Filter(
        'System Health Dashboard',
        DateAdd(Start_DT_UTC, _UTCOffSet, Hours) <= DateAdd(_FirstDayInView, ThisItem.Value, Days),
        ((DateAdd(End_DT_UTC, _UTCOffSet, Hours) >= DateAdd(_FirstDayInView, ThisItem.Value, Days)) || (IsBlank(End_DT_UTC)))
    )
)

but the icon is still showing up starting on 8/31, even though that's the UTC start date, and local start date would be 8/30.

[v-yutliu-msft]

Hi @abrae005 ,

Please notice two things:

1)in powerapps, default time zone is local time zone.

2)in sharepoint list, its time zone is set by yourself.

So time in powerapps and in sharepoint maybe different.

To change a sharepoint list time zone, you should operate like this:
settings->site information->view all site sittings->regional settings

 The time zone you set in that will your sharepoint list time zone.

If you update time from powerapps to sharepoint list, system will convert time from local time zone to the time zone you set in sharepoint list automatically.

So I suggest you check:

1)local time zone in powerapps

2)time zone in sharepoint list

Then convert time based on your demands.

Best regards,

[abrae005]

Hi @v-yutliu-msft ,

Changing the time zone on the SharePoint site fixed the issue with the date showing incorrectly on the View/Edit form, and on the Details Popup. However, the calendar icons are still not showing correctly.

The "Visible" property on the Warning icon is:

/*Visible if calendar events are found on this day*/
!IsEmpty(
    Filter(
        'System Health Dashboard',
        Start_DT_UTC <= DateAdd(_FirstDayInView, ThisItem.Value, Days),
        ((End_DT_UTC >= DateAdd(_FirstDayInView, ThisItem.Value, Days)) || (IsBlank(End_DT_UTC)))
    )
)

I have an event that starts on 8/31 at 2:27 AM UTC, which is 8/30, 22:27 local time. The icon should show on 8/30, but it's only showing up starting 8/31. 

(If I click on the warning icon, it brings up the Details Popup, and that is showing correctly.

[v-yutliu-msft]

Hi @abrae005 ,

Could you tell me:

1)formula in this gallery's Items

2)what does "_FirstDayInView" and  "ThisItem.Value" represent?

Please notice that:
if you want to convert local time to utc time, you should use formula like this:

DateAdd( Now(), TimeZoneOffset(), Minutes )

If you want to convert utc to local time, you should use formula like this:

DateAdd( StartTime, −TimeZoneOffset( StartTime ), Minutes )

 I think your problem should be about converting time.

I suggest you read this doc in details to check how to converting time between utc and local time:

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/functions/function-dateadd-datediff

Best regards,

[abrae005]

Hi @v-yutliu-msft 

The Gallery Items formula isn't actually a formula, but a list of items. I am basically using the gallery to make the calendar layout. There are 42 items, because I have 6 rows (weeks) times 7 values (dates) per row.

[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41]

_FirstDayInView is set on the Screen's OnVisible. There are several values that are set to populate the calendar, and have the date numbers appear in the calendar boxes:

Set(_DateSelected, _CurrentDate);
Set(_FirstDayofMonth, DateAdd(_DateSelected, 1 - Day(_DateSelected), Days));
Set(_FirstDayInView, DateAdd(_FirstDayofMonth, -(Weekday(_FirstDayofMonth) - 2 + 1), Days));
Set(_LastDayofMonth, DateAdd(DateAdd(_FirstDayofMonth, 1, Months), -1, Days));
Set(_MinDate, DateAdd(_FirstDayofMonth, -(Weekday(_FirstDayofMonth) - 2 + 1),Days));
Set(_MaxDate, DateAdd(DateAdd(_FirstDayofMonth, -(Weekday(_FirstDayofMonth) - 2 +1), Days), 41, Days))

ThisItem.Value represents the date on the particular calendar square. So, for example, if I am looking at the square for September 1, the ThisItem.Value would be 9/1/2020.

[v-yutliu-msft]

Hi @abrae005 ,

When compare time in powerapps, you need to convert utc time to local time.

In powerapps, time zone is local time zone, not utc.

So please set  "Visible" property on the Warning icon:

/*Visible if calendar events are found on this day*/
!IsEmpty(
    Filter(
        'System Health Dashboard',
        DateAdd(Start_DT_UTC, _UTCOffSet, Hours) <= DateAdd(_FirstDayInView, ThisItem.Value, Days),
        ((DateAdd(End_DT_UTC, _UTCOffSet, Hours) >= DateAdd(_FirstDayInView, ThisItem.Value, Days)) || (IsBlank(End_DT_UTC)))
    )
)

Best regards,

[abrae005]

Hi @v-yutliu-msft ,

Thanks for your continued efforts trying to help me. Unfortunately, it's still not working. I added the DateAdd _UTCOffSet to the filter, and I'm still getting the same results.

In the screenshot I posted the other day, you can see that the Details Popup for that item is working correctly. And the "Text" for that label is below, no conversion for time zone. I just can't seem to figure out why it's displaying correctly (with no conversion) for a label, but it's not working (either with or without conversion) for the Icon filter.

"Outage Start: " & ThisItem.Start_DT_UTC

[abrae005 · Accepted solution]

Found a solution!

Thanks to this post https://powerusers.microsoft.com/t5/Building-Power-Apps/Calendar-gallery-display-circles-for-each-da... by @v-xida-msft , I was able to change my filter, and it worked.

For those future users who find this post on a google search and wonder exactly what I did, here is the new .Visible code for my icon:

/* Visible if Calendar Events are found on this day */
CountRows(
    Filter(
        'System Health Dashboard',
        DateValue(Text(Start_DT_UTC)) <= DateAdd(_FirstDayInView, ThisItem.Value, Days), 
        ((DateValue(Text(End_DT_UTC)) >= DateAdd(_FirstDayInView, ThisItem.Value, Days)) || (IsBlank(End_DT_UTC)))
    )
) > 0

(Basically, the difference is now instead of just looking at Start_DT_UTC or End_DT_UTC, I'm looking at the DateValue of the Text of those.)